This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A302947 #6 Sep 16 2020 19:00:46 %S A302947 0,3,86,6531,2104533,2766909379,13578993819785,252836915021232264, %T A302947 18036285050227905448214,4921162186957679442128426852 %N A302947 Number of n X n 0..1 arrays with every element equal to 1, 2, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302947 Diagonal of A302953. %e A302947 Some solutions for n=5 %e A302947 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..1..0. .0..0..0..0..0 %e A302947 ..0..0..0..0..0. .0..0..1..0..0. .0..1..0..0..1. .0..0..1..1..1 %e A302947 ..0..1..1..1..1. .0..0..0..1..1. .0..0..1..0..1. .0..0..0..1..0 %e A302947 ..1..1..0..1..1. .0..0..0..0..1. .0..0..0..1..0. .0..1..0..0..0 %e A302947 ..1..0..1..0..0. .1..1..0..1..0. .1..1..1..1..1. .1..0..1..0..0 %Y A302947 Cf. A302953. %K A302947 nonn %O A302947 1,2 %A A302947 _R. H. Hardin_, Apr 16 2018